Alkylation



United States Patent 3,275,702 ALKYLATION Tom Hutson, Jr., Bartlesville,Okla., assignor to Phillips Petroleum Company, a corporation of DelawareFiled Aug. 16, 1963, Ser. No. 302,537 4 Claims. (Cl. 260-671) Thisinvention relates to an improved alkylation process. In one aspect, thisinvention relates to a process for the production of linear detergentbase alkylates. In another aspect, this invention relates to theproduction of high molecular weight detergent alkylates from linearlolefins and aromaic hydrocarbons. In a further aspect, this inventionrelates to the formation of preferentially substituted detergentalkylates by conducting the alkylation process in a manner which eitheravoids or substantially reduces the formation of alkylates other thanthe desired alkylates. In a still further aspect, this invention relatesto a method for forming detergent alkylates from l-olefins and benzenein order to preferentially achieve the 2-phenyl alkylates by suppressingdouble bond shift during the course of the alkylation reaction.

It is well known that aromatic hydrocarbons such as benzene, toluene,naphthalene, and the like may be reacted in the presence of an acidcatalyst with a linear l-olefin to produce the corresponding alkylatedaromatic hydrocarbons. However, detergent alkylate bases made fromlinear l-olefins and aromatic hydrocarbons such as benzene usingconventional anhydrous hydrofluoric acid catalyst consist of a mixtureof aromatic alkanes. Where benzene is used this mixture containsZ-phenyl, 3-phenyl, 4-phenyl, 5-phenyl and 6-pheny1 substitutionproducts and is believed to be the result of double bond shifting priorto alkylation. Such a mixture of phenyl alkanes, when sulfonated andformulated into detergent, produces a detergent of inferior quality ascompared with that produced from predominantly Z-phenylalkanes.

It is thus an object of this invention to provide an improved processfor the production of linear alkylates,

Another object of this invention is .to provide a process for thepreferential formation of 2-substituted aromatic alkanes.

Another object of this invention is to provide an improved process forthe production of alkylated benzenes suitable for use as detergentintermediates.

Other objects, aspects and the several advantages of the invention willbe apparent to those skilled in the art from a study of the accompanyingdisclosure, claims and drawmg.

I have now discovered a process for the formation of preferentiallysubstituted alkyl aromatics from aromatic hydrocarbons and linearl-olefins in the presence of HF catalyst wherein the formation ofaromatic compounds with substitutents, at positions other than the 2position is either excluded or substantially reduced. According to theinventive process, by utilizing an HF catalyst containing from 2 to 4,preferably from 2.5 to 3.5, weigh percent of a modifier selected fromthe group consisting of water and hydrogen, double bond shifting issuppressed prior to or during the alkylation reaction. Thuspredominantly the 2-substituted alkylates are produced. In addition tosuppressing the double bond shift, I have further discovered that byconducting the alkylation process in a tubular reactor maintained undercertain conditions, the 2-position alkylate production is furtherenhanced. Accordingly, by providing a reactor residence time within therange of 0.1 to 4.5 minutes while maintaining a reaction temperatureWithin the range of 40 to F. in the reaction zone and sutficientpressure to maintain all the materials in the liquid phase, thedetergent alkylate produced is of superior quality and is predominantlya material with the aromatic group in the 2-position of the alkyl chain.

These and other advantages of the present process will be apparent froman explanation of the accompanying drawing, in which is shown adiagrammatic illustration of one specific embodiment of the invention.Specific feed stocks are mentioned in the description, not as limitingthe scope of the disclosure but as an aid to clarity in explanation.

Referring to the drawing, an olefin concentrate such as dodecene-l ispassed to drier 10 through line 8 and introduced to mixing nozzle 14through line 12. Here the olefin concentrate is admixed with a molarexcess of an aromatic compound, such as benzene, drawn by conduit 16through drier 18 and through lines 20 and 22. Hydrofluoric acid catalystis admixed with the mixture by means of nozzle 24, and the resultingmixture is introduced into tubular reactor 26. The feed rates ofcatalyst, olefin and aromatic compounds are so adjusted as not only togive the desired mol ratios but also to provide a residence time in thetubular reactor 26 within the range of 0.1 to 1.0 minute. Sufficientpressure is maintained to keep the entire mass liquid while the reactiontemperature is maintained within the range of 40 to 100 F. Eflluent isdischarged from alkylation zone 26 through line 28 to separator 30,where it is divided by gravity into catalyst and hydrocarbon phases. Theheavier catalyst phases containing but little catalyst soluble productis recycled through line 32, cooler 34 and line 36 to mixing nozzle 24.Line 38 communicates with line 36 to provide for removal of HF catalystfor regeneration as required. Line 40, communicating with line 36,provides a means for introducing make-up catalyst or modifier into thealkylation system. The total hydrocarbon phase is removed through line42 to fractionator 44 from which unreacted benzene is removed throughline 46 for recycle to the alkylation zone. The remaining eflluent fromfractionator 44 is passed through line 48 to fractionator 50 whereinlight alkylates boiling within the range of 200 to 450 F. are removedvia line 52. The remaining effluent from fractionator 50 is withdrawnthrough line 54 and passed to fractionator 56, wherein the desiredlinear detergent alkylate is removed via line 58 and the heavy alkylateboiling above 650 F. is removed through line 60. The linear alkylatethus produced is passed on to subsequent treatment for conversiontodetergents or to storage as desired.

Catalyst activity is maintained at a high level by drawing off portionsof the used catalyst in line 36 through line 38 and passing it to acatalyst regeneration zone, not shown. The regenerated catalyst,together with such make-up as required, is returned to the system vialine 40.

In the accompanying diagrammatical drawing, reference to various piecesof equipment such as pumps, gauges and other equipment which areobviously necessary to actually operate the process have beenintentionally omitted. Only suflicient equipment to operate theinventive process has been illustrated, and it is intended that no unduelimitation be read into the invention by reference to the drawing andthe discussion thereof.

The following example will further serve to illustrate the invention.

3 Example A comparative alkylation of benzene and dodecene-l was carriedout under the following conditions:

High Water Convcnin Acid and tional Short Contact Time Test No 1 2Reactor Stirred Tube Time 4. 0.33 Tempcrature,F 50 50 Pressure, p.s.i.ga 125 126 Benzene/Olefin M01 Ratio. 19. 8 20. 3

HF Acid Data. Wt. percent:

Total Acidi y 92.31 88.73 Soluble Oil 0. 01 0.00 Inorganic Fluori 0.550.88 er 0.45 3. 13

Alkylate Analysis:

5 and 6-pheny1-dodecane 48.0 30. 2 4-phcnyl-dodecane 18. O 13. 83-phenyl-dodecane 1G. 7 19. 6 2-phenyl-dodecane 17. 3 36. 4l-phenyl-dodecane O 0 The above data indicate :that by reducingresidence time while producing sufficient modifier to prevent doublebond shift, a significant reduction is obtained in the various alkylatesproduced with a corresponding increase in the production of thepreferred 2-substituted alkylates.

While the above example has illustrated the present invention by the useof dodecene-l, it is to be understood that other l-olefins having 8 to18 carbon atoms per molecule are useful in the inventive alkylationprocess. Likewise, in addition to the illustrated benzene, othersuitable aromatic compounds include xylene and the like. In someinstances, highly aromatic naphtha fractions, such as can be obtainedfrom thermally cracked naphthas, can be employed as a source ofalkylatable aromatic hydrocarbon.

The catalyst employed in the alkylation zone is prefer ably a liquidhydrofluoric acid in concentration of 50 percent or higher. The reactionconditions will generally be in the range of 40 to 100 F. with apressure suificient to prevent vaporization of the catalyst. Forexample, a pressure between 25 and 50 p.s.i.g. is sufficient. Flow ratesof reactants should be maintained such that a residence time between 0.1and 4.5 minutes and preferably 0.1 to 1 minute will be provided in thealkylation zone. The mol 4 ratio of aromatic to l-olefin entering toreaction zone should be between 10.1 and 25:1 but preferably about 20:1.The ratio of catalyst employed to total hydrocarbons in the reactionzone should be in the range of about 1:5 to 2:1, but preferably about1:3 to 1:1.

By the term preferential alkylation as employed herein, there is meantthat the alkylate formed by having the modifier included in the catalystsystem is predominantly the 2 substituted alkylate. Thus the use of themodifier suppresses alkylation at the other positions available.

Reasonable variations and modifications can be made or followed in viewof the foregoing disclosure without departing from the spirit or thescope thereof.

I claim:

1. A process for the preferential alkylation of an aromatic hydrocarbonwith an olefinic hydrocarbon in order to achieve predominantly Z-arylalkanes which comprises introducing said aromatic hydrocarbon and saidolefinic hydrocarbon into an alkylation zone at a ratio of about 10:1 to25 :1 in contact with an HP acid catalyst, said catalyst containing from2 to 4 weight percent based on total catalyst employed, a modifierselected from the group consisting of hydrogen and water, maintainingthe resulting alkylation reaction mixture in said alkylation zone for atime in the range of 0.1 to 4.5 minutes and at a temperature within therange of 40 to 100 F. and thereafter recovering the resultingpreferentially formed alkylate as a product of the process.

2. The process of claim 1 wherein said modifier is present in an amountwithin the range of 2.5 to 3.5 weight percent.

3. The process of claim 1 wherein the reaction mass has a residence timein the alkylation zone in the range of 0.1 to 1.0 minute.

4. A process according to claim 1 wherein said aromatic hydrocarbon isbenzene and said olefin hydrocarbon is dodecene-l and the ratio ofaromatic hydrocarbon to olefinic hydrocarbon is about 20: 1.

References Cited by the Examiner UNITED STATES PATENTS 2,404,340 7/1946Zimmerman 260671 2,431,685 12/1947 Cade 260683.51 2,452,812 11/1948Wachter 260671 X 3,206,524 9/1965 Plaster 2 -671 X DELBERT E. GANTZ,Primary Examiner.

PAUL M. COUGHLAN, Examiner.

C. R. DAVIS, Assistant Examiner.

1. A PROCESS FOR THE PERFERENTIAL ALKYLATION OF AN AROMATIC HYDROCARBONWITH AN OLEFINIC HYDROCARON IN ORDER TO ACHIEVE PREDOMINANTLY 2-ARYLALKANES WHICH COMPRISES INTRODUCING SAID AROMATIC HYDROCARBON AND SAIDOLEFINIC HYDROCARBON INTO AN ALKYLATION ZONE AT A RATIO OF ABOUT 10:1 TO25:1 IN CONTACT WITH AN HF ACID CATALYST, SAID CATALYST CONTAINING FROM2 TO 4 WEIGHT PERCENT BASED ON TOTAL CATALYST EMPLOYED, A MODIIFIERSELECTED FROM THE GROUP CONSISTING OF HYDROGEN AND WATER, MAINTAININGTHE RESULTING ALKLYATION REACTION MIXTURE IN SAID ALKYLATION ZONE FOR ATIME IN THE RANGE OF 0.1 TO 4.5 MINUTES AND AT A TEMPERATURE WITHIN THERANGE OF 40 TO 100*F. AND THEREAFTER RECOVERING THE RESULTINGPREFERENTIALLY FORMED ALKYLATE AS A PRODUCT OF THE PROCESS.